Two-sided cooking apparatus or clamshell cooking systems are capable of simultaneously cooking two sides of various food products, such as, hamburger patties, sausage patties, chicken, or other foodstuffs. Clamshell cooking systems are often utilized in the fast-food industry because they reduce the overall cooking time associated with the foodstuffs, such as, frozen hamburger patties, and the amount of operator attention required for cooking the foodstuffs.
The clamshell cooking system generally includes an upper cooking plate or platen and a lower cooking plate or platen. The upper cooking platen is coupled to a platen support arm for swinging movement between a lower cooking position overlying the lower cooking platen and a raised position inclined upwardly from the lower cooking platen. The upper cooking platen can be manually or automatically moved between the lower cooking position and the raised position.
When the upper cooking platen is in the lower cooking position, it overlies the lower cooking platen and is separated from the lower cooking platen by a gap. The gap is generally set to a distance associated with the thickness of the foodstuff which is being cooked. The gap can be manually or automatically adjusted so that the foodstuff is appropriately cooked between the upper cooking platen and the lower cooking platen.
The gap between the upper cooking platen and the lower cooking platen must be set to accommodate the particular size or thickness of the foodstuff, such as, a hamburger patty, being cooked. For example, hamburger patties are preformed in several different nominal sizes (a quarter pound patty has a larger thickness than a regular patty).
Additionally, the gap must be adjusted during the cooking operation to accommodate the decrease in size of the hamburger patty as it is cooked. Hamburger patties are generally frozen for storage and transportation. The frozen patties are relatively rigid when initially placed on the lower cooking platen, and, if the upper cooking platen rests only on the thickest patty or patties, even small differences in the thickness of the patties in the group being cooked could delay good heat-transmitting contact between the upper platen and some of the thinner patties. Poor heat transmission results in uneven cooking of the patties. Further, the patties often soften and shrink or decrease in thickness as they thaw and cook. The gap must accommodate this change in thickness during the cooking operation.
Further still, the gap must be set so that the hamburger patty is protected from the weight of the upper cooking platen. If the weight of the upper cooking platen is unrestrained or uncontrolled, the upper cooking platen could excessively compress or compact the hamburger patties and adversely affect the texture and appearance of the cooked patties.
Thus, clamshell cooking systems present several special problems related to the adjustment of the gap between the upper and lower cooking platens. These problems include accommodating variations in initial thickness of the individual patties in the group being cooked, accommodating the decrease in thickness of the patties that occurs during cooking, preventing excess compaction of the patties, and accommodating different groups of patties of nominally different thicknesses.
Heretofore, clamshell cooking systems have relied on gravity to force the upper cooking platen onto groups of patties on the lower platen. Platen stops also can be provided to control the minimum spacing (the smallest acceptable spacing or gap) between the upper platen and the lower platen during cooking, thereby preventing excessive compaction of the cooked patties. The platen stops generally had to be manually manipulated to adjust the size of the gap between the upper cooking platen and the lower cooking platen. The use of manually manipulated stop pins is disadvantageous because the stop pins reduce the usable cooking area on the upper and lower platens and make it difficult to clean the upper platen. Further, stop pins which are near or in the cooking area are susceptible to grease and other debris which tended to bake onto the stop pins and to impede their adjustment. Further still, the manual adjustment of the gap can lead to operator error, particularly where several knobs have to be adjusted on a single platen.
In another prior system, the gap can be automatically set by adjusting a cam coupled to the platen support arm. However, the cam and mechanical linkages are exposed to grease and other debris which can impede the adjustment of the gap. Also, the cam is not capable of providing the necessary float to accommodate the variations in thicknesses of patties. Spring-loaded stop pins similar to the pins discussed above are required to provide the necessary float.
Thus, there is a need for a two-sided cooking system which includes an automated gap adjustment mechanism. Further, there is a need for an automatic gap adjustment system which does not rely on stop pins to provide float.